Publications

2000

• Tenue d'ancrages LMS sur fonds coralliens indurés
  
  • Luong Minh-Phong
  • Habib Pierre
  Rev. Franç. Géotech., 2000, 89, pp.29-32. Cet article rapporte une expérimentation en vraie grandeur d’un système d’ancrage LMS à forte capacité de tenue dans un fond marin constitué de calcaires coralliens indurés de la Polynésie française. Les résultats ont mis en évidence la possibilité de reprise des efforts dans des zones où la compacité du terrain exclut la mise en œuvre des ancres marines traditionnelles. La sécurité de tenue ne dépend pratiquement pas de la couche superficielle souvent hétérogène. La reprise des efforts verticaux réduit très sensiblement la longueur des lignes de mouillage. Le poids réduit de l’ancrage, grâce à une efficacité exceptionnelle (> 100), est un avantage technique et économique de mise en œuvre, extrêmement appréciable par rapport aux ancres marines de type classique. (10.1051/geotech/1999089029)
  DOI : 10.1051/geotech/1999089029
• Shut-in pressure tests - case studies
  
  • Bérest P.
  • Brouard B.
  • Durup G.
  , 2000, pp.105-125. No abstract provided
• Structural morphology and relaxation spectra of viscoelastic heterogeneous materials
  
  • Beurthey Stéphan
  • Zaoui André
  European Journal of Mechanics - A/Solids, Elsevier, 2000, 19, pp.1-16. We analytically derive the relaxation spectra of a two-phase isotropic material whose phases are isotropic Maxwell media, according to the classical and to the generalized self-consistent schemes. Whereas these spectra are continuous in both cases, they exhibit strong differences which can be associated with the different underlying morphology, either symmetrical (polycrystal-type) in the first case or asymmetrical (composite-type) in the second case. The treatment is extended to the (N+1)-phase model which allows us to deal with coated inclusions or with an interphase between the matrix and the inclusions: the interphase is shown to strongly modify the resultant spectrum. More general cases are then considered for different kinds of constitutive behaviour as well as for coated fibre reinforced composites. As a whole, the spectral analysis method appears to be an efficient tool for the investigation of the connection between structural morphology and the overall behaviour of viscoelastic heterogeneous materials. (10.1016/S0997-7538(00)00157-1)
  DOI : 10.1016/S0997-7538(00)00157-1
• Stability Analysis of Incipient Folding and Faulting of an Elasto-Plastic Layer on a Viscous Substratum
  
  • Leroy Yves
  • Triantafyllidis Nicolas
  , 2000, pp.109-139. The initiation of two modes of instability, viz. folding and faulting, is investigated theoretically for an elasto-plastic, frictional- cohesive layer which is underlain by a viscous substratum. The destabilizing factors that are allowed to come into play are the tectonic stress, buoyancy forces resulting from a gravitationally unstable density stratification, and the redistribution of material at the top surface by erosion and deposition processes. The bending stiffness of the overburden, a non-linear function of stress, has a stabilizing influence. A variational formulation of the stability problem allows one to detect the onset of global modes of instability, such as folds and surface modes for compression as well as neck-type modes for extension. Predictions of these global modes remain valid as long as the local condition of strong ellipticity is satisfied. Failure of this condition marks the onset of discontinuities in the velocity field, which are characteristic of localized faulting. The sensitivity of these predictions to the assumed behaviour of the overburden and substratum materials is explored for a prototype representative of a dip section through the Campos salt basin on the Brazilian continental margin. These results illustrate the importance of a proper selection of analogue materials for the design of physical laboratory models. This point is underscored by employing a deformation theory of plasticity which could be seen to reproduce in a simple manner the accommodation of bulk deformation by slip along a population of pervasive small faults in sedimentary rocks as well as in analogue materials, such as sands, used in the laboratory. A historical account of the use of deformation theories of plasticity in stability analyses and a derivation of the relevant incremental moduli are also given in this paper. (10.1007/978-3-642-59617-9_6)
  DOI : 10.1007/978-3-642-59617-9_6
• Brake squeal: a problem of flutter instability of the steady sliding solution ?
  
  • Moirot Franck
  • Son Nguyen Quoc
  Archives of Mechanics, 2000, 4-5, pp.645-662. Brake squeal results from friction-induced vibrations. This phenomena is considered here and interpreted as a flutter instability of the steady sliding solution of an elastic solid in unilateral contact with friction with a moving obstacle. A mechanical analysis of the governing equations is given, in particular to obtain the steady sliding solution. The stability analysis of this solution is discussed. A numerical analysis by the finite element method is performed in order to compute the steady sliding solution and to discuss its stability for an automotive disk brake. The validation of the numerical procedure is examined in relation with some analytical results of the literature.
• Resource-bounded relational reasoning: induction and deduction through stochastic matching
  
  • Sebag Michèle
  • Rouveirol Céline
  Machine Learning, Springer Verlag, 2000, 38 (1-2), pp.41-62. One of the obstacles to widely using first-order logic languages is the fact that relational inference is intractable in the worst case. This paper presents an any-time relational inference algorithm: it proceeds by stochastically sampling the inference search space, after this space has been judiciously restricted using strongly-typed logic-like declarations. We present a relational learner producing programs geared to stochastic inference, named STILL, to enforce the potentialities of this framework. STILL handles examples described as definite or constrained clauses, and uses sampling-based heuristics again to achieve any-time learning. Controlling both the construction and the exploitation of logic programs yields robust relational reasoning, where deductive biases are compensated for by inductive biases, and vice versa. (10.1023/A:1007629922420)
  DOI : 10.1023/A:1007629922420
• On a new methodology for quantitative modeling of fretting fatigue
  
  • Dang Van Ky
  • Maitournam Habibou
  , 2000, pp.538-552. A new intrinsic methodology for the prediction of fretting fatigue failure of a structure is presented. It is based, first, on the evaluation of local relevant thermomechanical parameters by new thermoelastoplastic computational methods (direct cyclic method) and, second, on the systematic use of the Dang Van multiaxial high-cycle fatigue criterion. For the validation of this proposal, numerical simulations of fretting fatigue tests on a particular experimental setup considered as a structure are performed. The resulting prediction of the experimental fretting fatigue map in relation to plastic and fatigue material properties is good. (10.1520/STP14753S)
  DOI : 10.1520/STP14753S
• Dynamic testing of fibre polymer matrix composite plates under in-plane compression
  
  • Gary Gérard
  • Zhao H.
  Composites Part A: Applied Science and Manufacturing, Elsevier, 2000, 31, pp.835-840. Experimental investigations of the failure strength of fibre reinforced polymer matrix composite plates under compressive impact loading is presented in this paper. A split Hopkinson pressure bar (SHPB) is used to measure these properties. The specimen being a plate, its cross-sectional area is small compared with the area of the bars and the failure strength is weak. One has to then use low impedance bars made of a viscoelastic material. Subsequent experimental problems, such as dispersion corrections in viscoelastic bars, are analysed. One also has to use a special anti-buckling device to prevent the overall buckling of the specimen. It is shown that the presented SHPB system provides a precise measurement of forces and displacements at both ends of the specimen. A special attention is then given to the analysis of the test, especially in situations where a non-homogeneous state of stress in the specimen in observed. (10.1016/S1359-835X(00)00026-9)
  DOI : 10.1016/S1359-835X(00)00026-9
• Science et règlement
  
  • Salençon Jean
  , 2000, pp.213-221.
• Thermomechanical description of moving discontinuities: Application to wear
  
  • Stolz Claude
  , 2000. The propagation of moving surface inside a body is analysed within the framework of thermomechanical couplings, when the moving surface is associated with an irreversible change of mechanical properties.The moving surface is a surface of heat sources and of entropy production, intensities of which are related to particular energy release rates defined in terms of Hamiltonian gradients. As examples, we analyse the evolution of partial damage in a composite sphere and a model for study the contact wear phenomena between two bodies.
• Percolation mécanique'' : pertinence des modèles classiques en viscoélasticité linéaire et nouvelles approches
  
  • Bornert Michel
  • Aussant F.
  • Zaoui A.
  , 2000. No abstract provided
• A critical study of SHPB test on the materials involved in crash problems
  
  • Zhao H.
  • Gary G.
  , 2000. No abstract provided
• Intelligent optimal design of naval structures: is it possible ?
  
  • Zarka J.
  , 2000. No abstract provided
• On the role of fluids in the cracks of elastic materials
  
  • Feraille Fresnet Adélaïde
  • Bui Huy Duong
  • Ehrlacher Alain
  , 2000, pp.53-64.
• Field Data vs. Theoretical Model to Quantify Drilling Efficiency and Disruption
  
  • Putot Claude
  • Perreau Philippe
  • Constantinescu Andrei
  SPE Drilling and Completion, Society of Petroleum Engineers, 2000, 15, pp.118-124. Mechanical and kinematics data at the bit have been collected during drilling operations and organized to identify optimal drilling efficiency. Transitional conditions towards abnormal behavior have been distinguished. Normal drilling is usually characterized by regular linear relationships between global control variables at the bit, which approximately correspond to an up scaling of a local Mohr Coulomb type failure mechanism of the rock. Most of our experimental data confirm this classical disposition. However, considerable departure from these relationships is noted, especially when there is BHA resonance or when there is partial balling at the bit. The field tests presented here allows us to verify classical theory and to draw up new guidelines for behavior in non- optimal or dangerous, evolving operating conditions, such as those that occur under poor cleaning conditions. The main features of a mechanical structuring model involving transition towards low efficiency conditions are presented, and it is shown how this model confirms our interpretation of field data. The model couples the drillability of rock and the general dynamics of the bit in an original and synthetic way. It makes it possible to understand and test the sensitivity of bit response to variables such as "weight on hook", torque on the drillstring and flow rate of the fluid. (10.2118/50579-MS)
  DOI : 10.2118/50579-MS
• Quelques exemples de vibrations et d'instabilité induites par le frottement
  
  • Nguyen Q. S.
  , 2000. No abstract provided
• Intelligent modelling of woven materials
  
  • Zarka Joseph
  • Doux Thierry
  , 2000.
• Plasticity of zirconium at intermediate temperatures: effect of a small quantity of sulfur
  
  • Ferrer F.
  • Bretheau Th.
  • Crépin Jérôme
  • Barbu A.
  , 2000. No abstract provided
• Optimal design of a beam with a direct link to CAD
  
  • Zarka J.
  • Hablot J. M.
  , 2000. No abstract provided
• Investigation expérimentale et modélisation micromécanique de la déformation locale à chaud d'aciers biphasés
  
  • Pinna Christophe
  • Bornert Michel
  , 2000.
• Détection et quantification thermique de particularités d'appui et de lésions superficielles chez les marcheurs de grand fond
  
  • Parganin D.
  • Loizeau J.
  • Luong M. P.
  • Genson F.
  , 2000. No abstract provided
• Instabilité du glissement stationnaire : application au crissement des freins
  
  • Moirot F.
  • Nguyen Q. S.
  , 2000. No abstract provided
• Brake squeal: a problem of flutter instability of the steady sliding solution?
  
  • Moirot Franck
  • Nguyen Quoc Son
  Archives of Mechanics, Polish Scientific Publishers Pwn, 2000, 52 (4-5), pp.645-661. Brake squeal results from friction-induced vibrations. This phenomenon is considered here and interpreted as a flutter instability of the steady sliding solution of an elastic solid in unilateral contact with friction with a moving obstacle. A mechanical analysis of the governing equations is given, in particular to obtain the steady sliding solution. The stability analysis of this solution is discussed. A numerical analysis by the finite element method is performed in order to compute the steady sliding solution and to discuss its stability for an automotive disk brake. The validation of the numerical procedure is examined in relation with some analytical results of the literature.
• Damage mechanism of Ti6AL4V substrats coated by tungsten based PVD layers under single particles impact loading
  
  • Graff G.
  • Stolz C.
  • Pradeilles-Duval R. M.
  • Sainte Catherine M.C.
  • Jomeaux S.
  • Penquer F.
  , 2000. No abstract provided
• Thermodynamical description of running discontinuities: application to wear
  
  • Stolz Claude
  , 2000.